Quantum Ring Infrared Photodetector Based On Droplet Epitaxy Technique

2009 ◽  
Vol 1208 ◽  
Author(s):  
Dali Shao ◽  
Jiang Wu ◽  
Zhenghua Li ◽  
Omar Manasreh ◽  
Vasyl P Kunets ◽  
...  
Keyword(s):  
Near Infrared ◽  
Droplet Epitaxy ◽  
Quantum Ring ◽  
Infrared Photodetector ◽  
Mid Infrared ◽  
Quantum Rings ◽  
Force Microscopy ◽  
Atomic Force ◽  
Infrared Spectral ◽  
Infrared Spectrometer

AbstractIn this work, we design and fabricate a GaAs quantum ring infrared photodetector. The lattice matched GaAs/Al0.3Ga0.7As quantum rings are grown by using molecular beam epitaxy technique. The morphology of the quantum rings are characterized by an atomic force microscopy. Normal incident configured photodetectors are fabricated by standard photolithography. The photoresponse spectra are measured by a Fourier transform infrared spectrometer and exhibit two broad bands in visible-near-infrared and mid-infrared spectral range. Using quantum rings as absorption medium, we observed visible-near-infrared response at a temperature as high as 300 K while mid-infrared response up to 140 K.

Type-II GaSb/GaAs Nanostructures Grown by Droplet Epitaxy with Various Ga Amounts

2015 ◽  
Vol 1131 ◽  
pp. 60-63 ◽  
Author(s):  
Maetee Kunrugsa ◽  
Somsak Panyakeow ◽  
Somchai Ratanathammaphan
Keyword(s):  
Quantum Dots ◽  
Atomic Force Microscopy ◽  
Optical Properties ◽  
Droplet Epitaxy ◽  
Formation Mechanisms ◽  
Type Ii ◽  
Quantum Rings ◽  
Force Microscopy ◽  
Atomic Force

We study the GaSb/GaAs nanostructures (NSs) grown by droplet epitaxy technique with various Ga amounts. Ga amount deposited on the GaAs (001) substrate was varied between 3-5 ML to form the different size and density of liquid Ga droplets. The Sb flux was subsequently irradiated to crystallize the droplets. Morphology of GaSb NSs was investigated by atomic force microscopy (AFM). Quantum rings were obtained after crystallizing 3-ML Ga droplets, whereas some kind of quantum dots were formed after crystallizing 4-and 5-ML Ga droplets. The formation mechanisms leading to the different structure are discussed. The photoluminescence (PL) measurement was performed to examine the optical properties of GaSb/GaAs NSs.

Photodetectors Fabricated from Strain-free GaAs Coupled Quantum Dots

2009 ◽  
Vol 1208 ◽  
Author(s):  
Jiang Wu ◽  
Dali Shao ◽  
Omar Manasreh ◽  
Alvason Zhenhua Li ◽  
Zhiming M Wang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Infrared Spectrum ◽  
Near Infrared ◽  
Infrared Range ◽  
Intersubband Transitions ◽  
Coupled Quantum Dots ◽  
Mid Infrared ◽  
Atomic Force ◽  
Infrared Spectral ◽  
Lattice Matched

AbstractIn this article, an alternative strain-free growth mode is presented where GaAs coupled-quantum dots are grown on lattice matched AlGaAs. The coupled quantum dots were grown at 550 °C in a molecular beam epitaxy system. The GaAs quantum dots were characterized by using a photoluminescence technique and an atomic force microscope. The photodetector was fabricated into normal incident configuration and photoconductivity spectra were measured covering the mid-infrared spectrum of 2.0 – 8.0 micron (intersubband transitions) and the visible-near-infrared spectrum of 0.5 – 0.9 micron (interband or exciton transitions). The photoresponse spectra in mid-infrared spectral range were found to exist at temperatures lower than 80 K, while the photoresponse spectra in the visible-near-infrared range were observed at temperatures as high as 300 K.

scholarly journals ALD Deposited ZnO:Al Films on Mica for Flexible PDLC Devices

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1011
Author(s):  
Dimitre Z. Dimitrov ◽  
Zih Fan Chen ◽  
Vera Marinova ◽  
Dimitrina Petrova ◽  
Chih Yao Ho ◽  
...  
Keyword(s):  
Near Infrared ◽  
Atomic Layer ◽  
Optical Transmittance ◽  
Force Microscopy ◽  
Flexible Polymer ◽  
Layer Deposition ◽  
Polymer Dispersed ◽  
Muscovite Mica ◽  
Infrared Spectral ◽  
Continuous Bending

In this work, highly conductive Al-doped ZnO (AZO) films are deposited on transparent and flexible muscovite mica substrates by using the atomic layer deposition (ALD) technique. AZO-mica structures possess high optical transmittance at visible and near-infrared spectral range and retain low electric resistivity, even after continuous bending of up to 800 cycles. Structure performances after bending tests have been supported by atomic force microscopy (AFM) analysis. Based on performed optical and electrical characterizations AZO films on mica are implemented as transparent conductive electrodes in flexible polymer dispersed liquid crystal (PDLC) devices. The measured electro-optical characteristics and response time of the proposed devices reveal the higher potential of AZO-mica for future ITO-free flexible optoelectronic applications.

Self-Assembled GaAs Quantum Rings by MBE Droplet Epitaxy

2007 ◽  
Vol 121-123 ◽  
pp. 541-544
Author(s):  
She Song Huang ◽  
Zhi Chuan Niu ◽  
Jian Bai Xia
Keyword(s):  
Molecular Beam ◽  
Single Photon ◽  
Photon Emission ◽  
Molecular Beams ◽  
Semiconductor Nanostructures ◽  
Droplet Epitaxy ◽  
Single Photon Emission ◽  
Quantum Rings ◽  
Atomic Force ◽  
Surface Migration

Fabrication of semiconductor nanostructures such as quantum dots (QDs), quantum rings (QRs) has been considered as the important step for realization of solid state quantum information devices, including QDs single photon emission source, QRs single electron memory unit, etc. To fabricate GaAs quantum rings, we use Molecular Beam Epitaxy (MBE) droplet technique in this report. In this droplet technique, Gallium (Ga) molecular beams are supplied initially without Arsenic (As) ambience, forming droplet-like nano-clusters of Ga atoms on the substrate, then the Arsenic beams are supplied to crystallize the Ga droplets into GaAs crystals. Because the morphologies and dimensions of the GaAs crystal are governed by the interplay between the surface migration of Ga and As adatoms and their crystallization, the shape of the GaAs crystals can be modified into rings, and the size and density can be controlled by varying the growth temperatures and As/Ga flux beam equivalent pressures(BEPs). It has been shown by Atomic force microscope (AFM) measurements that GaAs single rings, concentric double rings and coupled double rings are grown successfully at typical growth temperatures of 200°C to 300°C under As flux (BEP) of about 1.0×10-6 Torr. The diameter of GaAs rings is about 30-50 nm and thickness several nm.

Determination of Wavelength Accuracy in the Near-Infrared Spectral Region Based on NIST's Infrared Transmission Wavelength Standard SRM 1921

2000 ◽  
Vol 54 (3) ◽  
pp. 450-455 ◽  
Author(s):  
Stephen R. Lowry ◽  
Jim Hyatt ◽  
William J. McCarthy
Keyword(s):  
Reference Material ◽  
Standard Reference Material ◽  
Spectral Region ◽  
Near Infrared ◽  
Cost Effective ◽  
Infrared Transmission ◽  
Internal Reference ◽  
Mid Infrared ◽  
Infrared Spectral Region ◽  
Infrared Spectral

A major concern with the use of near-infrared (NIR) spectroscopy in many QA/QC laboratories is the need for a simple reliable method of verifying the wavelength accuracy of the instrument. This requirement is particularly important in near-infrared spectroscopy because of the heavy reliance on sophisticated statistical vector analysis techniques to extract the desired information from the spectra. These techniques require precise alignment of the data points between the vectors corresponding to the standard and sample spectra. The National Institute of Standards and Technology (NIST) offers a Standard Reference Material (SRM 1921) for the verification and calibration of mid-infrared spectrometers in the transmittance mode. This standard consists of a 38 μm-thick film of polystyrene plastic. While SRM 1921 works well as a mid-infrared standard, a thicker sample is required for use as a routine standard in the near-infrared spectral region. The general acceptance and proven reliability of polystyrene as a standard reference material make it a very good candidate for a cost-effective NIR standard that could be offered as an internal reference for every instrument. In this paper we discuss a number of the parameters in a Fourier transform (FT)-NIR instrument that can affect wavelength accuracy. We also report a number of experiments designed to determine the effects of resolution, sample position, and optics on the wavelength accuracy of the system. In almost all cases the spectral reproducibility was better than one wavenumber of the values extrapolated from the NIST reference material. This finding suggests that a thicker sample of polystyrene plastic that has been validated with the SRM 1921 standard would make a cost-effective reference material for verifying wavelength accuracy in a medium-resolution FT-NIR spectrometer.

scholarly journals Correction: Mid-infrared spectroscopy and microscopy of subcellular structures in eukaryotic cells with atomic force microscopy – infrared spectroscopy

RSC Advances ◽  
2019 ◽  
Vol 9 (52) ◽  
pp. 30461-30461
Author(s):  
Luca Quaroni ◽  
Katarzyna Pogoda ◽  
Joanna Wiltowska-Zuber ◽  
Wojciech M. Kwiatek
Keyword(s):  
Atomic Force Microscopy ◽  
Infrared Spectroscopy ◽  
Eukaryotic Cells ◽  
Mid Infrared ◽  
Mid Infrared Spectroscopy ◽  
Force Microscopy ◽  
Atomic Force

Correction for ‘Mid-infrared spectroscopy and microscopy of subcellular structures in eukaryotic cells with atomic force microscopy – infrared spectroscopy’ by Luca Quaroni et al., RSC Adv., 2018, 8, 2786–2794.

scholarly journals The mid-infrared spectral characteristics of blazars

2014 ◽  
Vol 10 (S313) ◽  
pp. 93-94
Author(s):  
Howard A. Smith ◽  
F. Massaro ◽  
R. D'Abrusco ◽  
A. Paggi ◽  
P. Cowperthwaite ◽  
...  
Keyword(s):  
Large Fraction ◽  
Spectral Characteristics ◽  
Continuum Emission ◽  
Spectral Features ◽  
Mid Infrared ◽  
Infrared Spectral ◽  
Infrared Spectrometer ◽  
Γ Ray ◽  
Followup Studies ◽  
The Continuum

AbstractWe previously reported discovering that blazars have distinctive infrared colors as seen in the WISE mission. Of particular note are γ-ray blazars, the locus of whose colors roughly overlaps with QSOs contours but which is more tightly delimited and bluer than ULIRGs and Seyferts. Since a large fraction of γ-ray sources are unassociated with any point source, but are expected to be blazars, identifying a WISE-candidate blazar in the γ-ray source field enables efficient followup studies. In an effort to better understand why blazars have these colors, we reduced and analyzed Spitzer Infrared Spectrometer (IRS) measurements on 73 blazars of varying types, some at several epochs. These spectra can be used to study the continuum emission (non-thermal), and search for atomic or other spectral features.

Spectral Effects of Water in the 10,000 to 8000 cm−1 (1000 to 1250 nm) near Infrared Spectral Region. And, Can They Explain Previously Seen Effects of Water in the Spectral Region from 14,000 to 11,500 cm−1 (714 to 870 nm)?

1995 ◽  
Vol 3 (3) ◽  
pp. 143-153 ◽  
Author(s):  
James B. Reeves
Keyword(s):  
Spectral Region ◽  
Diffuse Reflectance ◽  
Near Infrared ◽  
Detailed Examination ◽  
Fourier Transform Spectrometer ◽  
High Moisture ◽  
Mid Infrared ◽  
Infrared Spectral ◽  
And Shifts ◽  
Optic Systems

The spectral region from 10,000 to 8000 cm−1 (1000 to 1250 nm) is often used for high moisture samples and fibre optic systems. The first objective of this work was to determine the effects of water on the spectra of various types of materials in this spectral region. The second objective was to determine the origin/nature of spectral effects/artifacts seen in the spectral region from 14,000 to 11,500 cm−1 (714 to 870 nm) when water was added to gums and proteins (increases in peak intensities and shifts in position due to the presence of water). Spectra were obtained by diffuse reflectance and transmission using a Fourier transform spectrometer. The results showed that the effects seen in the mid-infrared and near infrared from 8000 to 4000 cm−1 (1250 to 2500 nm) were also common in this part of the near infrared (i.e. peak shifts, loss of spectral features etc). Thus, the spectra of crystalline glucose and sucrose, while distinctively different as crystalline solids, were very similar when in solution and changes in the spectra of materials, such as acetone, pyridine and ethanol, were very similar in nature to those previously found in the near infrared from 8000 to 4000 cm−1 (1250 to 2500 nm). Finally, detailed examination of spectra in the region from 10,000 to 8000 or 6000 cm−1 (1000 to 1250 or 1667 nm) did not show any spectral effects similar to those seen in gums and proteins in the 14,000 to 11,500 cm−1 (714 to 870 nm) region. Thus, the nature of these effects is still unknown.

Near- versus Mid-Infrared Diffuse Reflectance Spectroscopy for the Quantitative Determination of the Composition of Forages and By-Products

1994 ◽  
Vol 2 (1) ◽  
pp. 49-57 ◽  
Author(s):  
James B. Reeves
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Diffuse Reflectance ◽  
Near Infrared ◽  
Reflectance Spectroscopy ◽  
In Vitro Digestibility ◽  
Mid Infrared ◽  
Infrared Spectrometer ◽  
By Products

The objective of this work was to explore the relative value of near- and mid-infrared diffused reflectance spectroscopy in determining the composition of forages and by-products. Sixty-seven samples consisting of 15 alfalfa, 16 tall fescue and 15 orchard grass hays, 10 corn stovers and 11 wheat straws at various stages of maturity were examined by diffuse reflectance using a scanning monochromator (1100–2500 nm), a Fourier near infrared spectrometer (10,000–4000 cm−1, 4 and 16 cm−1 resolution, neat and 5% sample in KBr) and a Fourier mid-infrared spectrometer (4000–400 cm−1, 4 and 16 cm−1 resolution, neat and 5% sample in KBr). Samples were analysed chemically and spectroscopically for fibres, in vitro digestibility, crude protein, nitrobenzene oxidation products and various measures of lignin content. The results showed that diffuse mid-infrared reflectance spectroscopy can perform as well as, and sometimes better than, diffuse near infrared spectroscopy in determining the composition of forages and by-products. In addition, Fourier near infrared spectroscopy did not perform as well as either near infrared using a scanning monochromator or the Fourier mid-infrared spectrometer. Finally, diluting samples with KBr was not beneficial for either Fourier based determinations. Additional work with more diverse data sets and various Fourier instrument configurations will be needed to further define the limits and usefulness of Fourier transform near- and mid-infrared spectroscopy in the determination of forage and by-product composition.

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